The invention relates to an electrical energy store.
For the storage of excess electrical current, which occurs, for example, when current is generated by renewable energy sources or by power plants operated in the optimal efficiency range, and for which there is temporarily no demand in the network, various technical alternatives are adopted. One of these is the rechargeable metal air battery (rechargeable oxide battery, ROB). ROBs are usually operated at temperatures of between 600° C. and 800° C. In this case, oxygen, which is supplied at a (positive) air electrode of the electrical cell, is converted into oxygen ions, is transported through a solid electrolyte and is brought to the opposite negative electrode. A reaction with a gaseous redox pair takes place there, which absorbs or emits electrons, depending on the charging or discharging process, the oxygen absorbed or emitted by the gaseous redox pair being transferred by the diffusion of the components of the redox pair to a porous, that is to say gas-permeable, and likewise oxidizable and reducible storage medium. On account of the high temperatures required for this process, the choice of material for the cell materials used and the design of the cell parts and also the arrangement of the storage medium are highly complex. In particular, the individual components become impaired after several redox cycles which are run at said operating temperatures.